听力文本

Six million years prior to the KT boundary, there were about twenty species of ammonites in the world's oceans.
第三纪界线前600万年，全球海洋中大约有20种菊石。
Three million years before the KT boundary, there were only fifteen or so
第三纪界线前300万年则是15种左右，
and one million years prior to the KT boundary we have less than half of what we started out with,
到了第三纪界线前100万年，只剩下不到最初的一半，
we have less than ten species, so the extinction event has already been going on for millions of years.
也就是不到10种菊石，这种渐渐消失的情况几百万年来一直都在持续。

The amazing thing is that we see the same pattern in the fish record,
令人吃惊的是同样的情况也发生在鱼类记录中，
we see the same pattern in the terrestrial reptile record, we even see the same pattern in the mammal record.
同样发生在陆生爬行类记录中，甚至同样发生在哺乳动物记录中。
All of these groups were undergoing an extinction event for millions of years
所有这些物种几百万年来都在经历灭绝事件，
and it would be absolutely amazing to me if dinosaurs weren't undergoing the same sort of extinction
如果恐龙没有经历同样的灭绝，我肯定会感到奇怪，
and indeed I think they were undergoing the same sort of long term extinction.
我确实认为它们同样经历了这种长期衰亡。

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